The primary goal is to develop new treatment strategies for childhood leukemias and lymphomas. The following projects are currently underway or in preparation: 1) Pilot Study of Non-Myeloablative, HLA-Matched Allogeneic Stem Cell Transplantation in Pediatric Leukemias and Lymphomas 2) Anti-CD22 Immunotoxin for Treatment of Leukemias and Lymphomas in Childhood 3) Anti-CD25 Immunotoxin for Treatment of Leukemias and Lymphomas in Childhood 4) Unconjugated Monoclonal Antibodies for Treatment Lymphomas In Childhood 5) EPOCH-Rituximab for HIV-Associated Non-Hodgkin's Lymphomas In Childhood 6) Comparative Oncology Investigations in Dogs as Model for Translational Studies in Pediatric Non-Hodgkin's Lymphomas 7) Pilot Study of Non-Myeloablative, T-Cell Depleted, Haploidentical Allogeneic Stem Cell Transplantation for Pediatric Leukemias and Lymphomas 8) Bench-to-Bedside Translational Development of WT1 Peptide-Transduced Allogeneic Dendritic Cell Vaccine for Childhood ALL